UnmappedColumnError when using mapped_args and version_id_col for optimistic concurrency control

[jruizaranguren]

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Example Code

import sqlalchemy as sa
from sqlmodel import Field, SQLModel, create_engine, Session

class Record(SQLModel, table=True):
    """Status list for credentials."""

    __tablename__ = "records"

    id: int | None = Field(default=None, primary_key=True, unique=True)
    name: str
    version: int = Field(sa_column=sa.Column(sa.Integer, nullable=False, default=1))
    
    __mapper_args__ = {
        "version_id_col": sa.Column("version", sa.Integer, nullable=False, default=1),
        "version_id_generator": False}
    
engine = create_engine("sqlite:////tmp/test.db")

record = Record(name="test")

SQLModel.metadata.create_all(engine, tables=[Record.__table__])

with Session(engine) as session:
    session.add(record)
    session.commit()
    session.refresh(record)

Description

• Create a model with a version_id_col so sqlalchemy can handle optimistic concurrency for me
• I expect the record is created
• Then I would expect that version will be checked in every update, but I'm stuck in the first step.

But I'm getting the following exception:
sqlalchemy.orm.exc.UnmappedColumnError: No column version is configured on mapper Mapper[Record(records)]...

Operating System

Linux

Operating System Details

Ubuntu 20.04

SQLModel Version

0.0.22

Python Version

3.10.12

Additional Context

SQLAlchemy documentation of version_id_col in mapper_args.

[jruizaranguren]

For those having similar problems, I found the solution, which is using the sa_column attribute of the model field:

class Record(SQLModel, table=True):
    """Status list for credentials."""

    __tablename__ = "records"

    id: int | None = Field(default=None, primary_key=True, unique=True)
    name: str
    version: int = Field(sa_column=sa.Column(sa.Integer, nullable=False, default=1))
    
    __mapper_args__ = {
        "version_id_col": version.sa_column,
        "version_id_generator": False}

[jruizaranguren]

I must reopen this question, because the above code does not fail, but it does not update the version column in the posgresql table.

Do anyone has successfully implemented optimistic concurrency with postgreslq?